#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define PORT 4000

#define MAXDATASIZE 100 // 一次能接收的最大字节数

int main(int argc, char const *argv[])
{
    int sockfd, numbytes;
    char buf[MAXDATASIZE];

    struct hostent *he;
    struct sockaddr_in their_addr; // 连接者的主机信息

    if(argc != 2) {
        fprintf(stderr, "usage: ./client_test1 hostname\n");
        exit(1);
    }

    if((he = gethostbyname(argv[1])) == NULL) { // 取得主机信息
        herror("gethostbyname");
        exit(1);
    }
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    their_addr.sin_family = AF_INET;
    their_addr.sin_port = htons(PORT);
    their_addr.sin_addr = *((struct in_addr*)he->h_addr);
    bzero(&(their_addr.sin_zero), 8);


    int opt = 1;
    socklen_t size = sizeof(int);
    // 防止bind: Address already in use
    if(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, size) == -1){
        perror("setsockopt");
        exit(1);
    }

    if(connect(sockfd, (struct sockaddr*)&their_addr, sizeof(struct sockaddr)) == -1) {
        perror("connect");
        exit(1);
    }

    if((numbytes = recv(sockfd, buf, MAXDATASIZE, 0)) == -1) {
        perror("recv");
        exit(1);
    }

    buf[numbytes] = '\0';
    printf("Received:%s\n",buf);
    close(sockfd);

    return 0;
}
